We have had this topic before, but USA isn't going to attack Iran. Comparing Iran and Iraq would be accurate when you remenber that Iran is a lot bigger than Iraq, and USA knew what kind of weaponery Iraq had. This isn't the same situatian with Iran, who have had to make its own weapons and buy weapons tech from the russians and chinese. And as said, some experts say that Iran would easilly wipe out the whole USAn fleet what they have for gulf of Persia. So Iran have a little better weaponery than Iraq had and the USAns doesn't really know what they have.
Now, USA had support from other countries with Afghanistan and Iraq, but Iraq have caused a political grave for many politicans in Europe and i doubt the new ones want to dig their graves, so USA would be more or less alone with their quest.
The real reason why Iran is part of the "Axis of evil", is because, like Iraq, Iran as a OPEC member wants to trade oil in Euros, meaning that they would trade with more stable currency and that doesn't fit for USA.
Having a nuclear weapon would mean that USA would have to be friends with you, they don't really fuck with the countries with nukes.
I am against Iran having nukes, but i also am against any other country having nukes, even the existing ones. So Iran having nuke isn't any worse than China, USA or France having one